The present invention relates generally to improvements in material-folding machines, and more specifically to improvements in machines for folding laundry articles such as bed sheets and blankets and the like.
The basic concept of utilizing pairs of folding rolls and a blade to move material between the rolls to obtain a fold has been known for a long time and is shown in such patents as U.S. Pat. No. 2,954,974 which issued to H. Kellett on Oct. 4, 1960, and Great Britain patent specification No. 1,377,089 published Dec. 11, 1974. Folding machines utilizing this concept have proven successful as long as the thickness of the material and the number of folds has been kept to a minimum. However, as the number of folds has increased and it has become common practice to fold materials of widely varied thicknesses, such as sheets and blankets, the machines have become overly complex due to the need to positively drive both rolls of at least the final pair and to drive them at equal speeds.
It has also been known to combine stackers with folding machines, but some such stackers have increased the size of the machines and others have not had a satisfactory means to move the folded material onto the stacker. Examples of stackers combined with folding machines can be seen in U.S. Pat. No. 3,190,640 which issued to R. L. Sjostrom on Jan. 22, 1965; U.S. Pat. No. 3,774,903 which issued to C. F. Sjoman et. al. on Nov. 27, 1973; U.S. Pat. No. 3,003,760 which issued to L. O. Scheu, Jr., et. al. on Oct. 10, 1961; and in U.S. Application Ser. No. 705,459 (now U.S. Pat. No. 4,057,241) which was filed July 15, 1976 as a continuation of application Ser. No. 546,924 which was filed on Feb. 4, 1975, now abandoned.